<template>
  <transition mode="out-in" v-on="on">
    <slot></slot>
  </transition>
</template>
<script lang="ts" setup>
  import { addClass, removeClass } from '@/utils/domUtils'

  defineOptions({ name: 'CollapseTransition' })

  const on = {
    beforeEnter(el) {
      addClass(el, 'collapse-transition')
      if (!el.dataset) el.dataset = {}

      el.dataset.oldPaddingTop = el.style.paddingTop
      el.dataset.oldPaddingBottom = el.style.paddingBottom

      el.style.height = '0'
      el.style.paddingTop = 0
      el.style.paddingBottom = 0
    },

    enter(el) {
      el.dataset.oldOverflow = el.style.overflow
      if (el.scrollHeight !== 0) {
        el.style.height = el.scrollHeight + 'px'
        el.style.paddingTop = el.dataset.oldPaddingTop
        el.style.paddingBottom = el.dataset.oldPaddingBottom
      } else {
        el.style.height = ''
        el.style.paddingTop = el.dataset.oldPaddingTop
        el.style.paddingBottom = el.dataset.oldPaddingBottom
      }

      el.style.overflow = 'hidden'
    },

    afterEnter(el) {
      removeClass(el, 'collapse-transition')
      el.style.height = ''
      el.style.overflow = el.dataset.oldOverflow
    },

    beforeLeave(el) {
      if (!el.dataset) el.dataset = {}
      el.dataset.oldPaddingTop = el.style.paddingTop
      el.dataset.oldPaddingBottom = el.style.paddingBottom
      el.dataset.oldOverflow = el.style.overflow

      el.style.height = el.scrollHeight + 'px'
      el.style.overflow = 'hidden'
    },

    leave(el) {
      if (el.scrollHeight !== 0) {
        addClass(el, 'collapse-transition')
        el.style.height = 0
        el.style.paddingTop = 0
        el.style.paddingBottom = 0
      }
    },

    afterLeave(el) {
      removeClass(el, 'collapse-transition')
      el.style.height = ''
      el.style.overflow = el.dataset.oldOverflow
      el.style.paddingTop = el.dataset.oldPaddingTop
      el.style.paddingBottom = el.dataset.oldPaddingBottom
    },
  }
</script>
